Not Applicable
1. Field of the Invention
This invention relates generally to sealant stream anomaly detecting assembly for detecting gas bubbles and solid contaminants (such as cured material) in a high-pressure sealant stream.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
It is known for a liquid stream bubble detecting assembly to include an ultrasonic transducer supported adjacent a liquid channel. In such assemblies the ultrasonic transducer is configured to emit ultrasonic sound energy pulses into a portion of the channel and to convert returning echo pulses into electrical impulses. These electrical impulses are proportional in strength to the amount of sound energy returned in the echo pulses.
Ultrasonic imaging or comparison is affected by the fact that different materials exhibit different acoustic properties. When mixed, different materials can be sampled in contrast to each other by the variations in both propagation velocity and shunt energy absorption that they exhibit as acoustic energy propagates through them. These differences in propagation and absorption can have a dramatic affect on the amplitude of return echoes. These variations in echo amplitude make it possible to discriminate between a uniform fluid medium and any anomalous, non-uniformities.
Liquids, for example, are relatively dense. Partly for this reason, liquids allow a relatively large amount of sound energy to echo back to an emitting transducer. Gasses on the other hand, partly because they are less dense than liquids, absorb most of the sound waves emitted by a transducer. Liquids containing bubbles are less dense than liquids having no bubbles and consequently absorb more sound waves than liquids having no bubbles.
Liquid stream bubble detecting assemblies are known to include drive electronics that are connected to the transducers of such assemblies and are calibrated to detect diminished or lost echo pulses. Drive electronics detect diminished or lost echo pulses in a given liquid by comparing the strength of the echo pulses to known signal strength levels encountered when ultrasonic sound energy is transmitted and echoed back through that given liquid when the liquid is bubble-free.
It is also known for liquid stream bubble detecting assemblies to include bubble indicators configured to flag a user that the assembly has detected a bubble in a liquid stream passing through the liquid channel.
For example, ultrasonic bubble detector assemblies are known to be used in detecting air bubbles in streams of blood flowing through blood transfusion pumps. One such system includes an ultrasonic transducer that is optimized for such medical applications and is supported adjacent a channel that carries blood through the transfusion pump. However, a blood transfusion pump bubble sensor assembly of this type would be unlikely to detect gas bubbles in a high-pressure stream of liquid sealant or to be able to withstand the high pressure or abrasive nature of a sealant stream.
In addition, ultrasonic bubble detecting assemblies are known to be used in detecting cavitation bubbles in hydraulic liquid flowing through a hydraulic system. However, a liquid stream bubble detecting assembly of this type would be unlikely to reliably detect gas bubbles in a high-pressure stream of liquid sealant or to be able to withstand an abrasive sealant stream.
What is needed is a liquid stream anomaly detecting assembly that can detect gas bubbles and/or solids in a stream of liquid sealant without failing due to the high pressures involved and the abrasive effect of sealant streams. What is also needed is such an assembly that is designed and built to work reliably in an industrial environment that subjects the assembly to such factors as electrical noise, temperature changes, vibration, motion and a variety of sealant materials to be inspected for bubbles and/or immersed solids. To be adaptable to such an environment it is also desirable that such an assembly be easy to repeatedly adjust and calibrate.
The invention is a sealant stream anomaly detecting assembly for detecting gas bubbles, immersed solids such as cured sealant and foreign objects, and/or other such anomalies in a high-pressure sealant stream. The assembly includes an ultrasonic transducer supported on a manifold defining a sensing chamber portion of a fluid channel. The transducer is configured to convert electrical input voltage pulses into ultrasonic acoustic energy pulses and to propagate the acoustic energy pulses through the manifold and into the sensing chamber. The transducer is also configured to receive resulting echo pulses from a back wall of the sensing chamber and to convert the echo pulses into electrical output impulses. An electronics module includes drive electronics connected to the transducer. The module is configured to receive the electrical output impulses from the transducer and to detect diminished and lost echo pulses by comparing the output impulse strength values for a given fluid passing through the sensing chamber to a known output impulse strength value for that same type of fluid having no bubbles or immersed solids. The sealant stream anomaly detecting assembly also includes an anomaly indicator connected to the electronics module and configured to flag a user in response to a signal from the electronics module indicating that the assembly has detected a bubble in a fluid stream passing through the fluid channel.
The transducer has a flat front emitter surface that lies flat against a flat manifold outer surface to provide superior acoustic energy pulse coverage throughout the sensing chamber. Increased pulse coverage results in improved anomaly detecting ability.
The invention also includes a method for detecting gas bubbles or immersed solids in a high-pressure sealant stream. According to this method one can detect gas bubbles or immersed solids in a high-pressure sealant stream by providing a sensing chamber in a fluid channel, providing an ultrasonic transducer, associated drive electronics and sensing chamber, connecting the ultrasonic transducer and associated drive electronics to the sensing chamber and connecting the anomaly indicator to the drive electronics. A fluid to be inspected for the presence of bubbles or immersed solids is then passed through the sensing chamber and the drive electronics are actuated to operate the transducer and detect bubbles or immersed solids in the fluid passing through the sensing chamber. The anomaly indicator is actuated to indicate to an operator and/or supervisory controller when the transducer and drive electronics detect a bubble in the fluid passing through the sensing chamber.